Espy explains cloud formation by thermal updraft. He concludes that storm winds should therefore point radially towards the eye instead of rotating round it, in order to fill in the low pressure there. He is wrong on this point in terms of observational fact. Redfield is already groping towards the solution of the contradiction, thinking that storm rotation has to do with Earth's rotation. Reid observes that storms rotate opposite ways in the northern and southern hemispheres. The missing concept is the Coriolis Effect.